The invention is directed to a process for the production of 2-cyanopyrazine by catalytic reaction of 2-methylpyrazine with ammonia and oxygen at elevated temperature. It is particularly directed to catalysts for this purpose made of compounds of the elements antimony, vanadium, and oxygen, and at least one of the elements iron, copper, titanium, cobalt, manganese, and nickel, as well as the process for producing the catalysts.
There are known several processes for the production of 2-cyanopyrazine from 2-methylpyrazine through its reaction with ammonia and oxygen at elevated temperature in the gas phase. They differ through the reaction conditions and especially through the catalysts. Among the processes and catalysts only those are suitable for use on an industrial scale which show good selectivity and simultaneously result in high space-time-yields.
It is known to use as catalyst for the reaction of 2-methylpiperazine to form 2-cyanopyrazine compounds of the elements molybdenum, vanadium, and cobalt with oxygen, in a given case, on a carrier such as aluminum oxide (Beutel U.S. Pat. No. 3,555,021). This process also in the case of the reaction of 2-methylpyrazine to 2-cyanopyrazine only results in small amounts.
Besides it is known to use as catalyst for the reaction of 2-methylpyrazine to form 2-cyanopyrazine divanadium pentoxide in admixture with potassium sulfate on carriers such as aluminum oxide (Japanese publication No. 49-30382). This process results in only moderate yields and besides requires a large excess of ammonia.
Furthermore, it is known to use for the reaction of alkyl substituted heteroaromatics to form the corresponding CN-substituted compound catalysts which are produced from mixtures which contain antimony and vanadium in the atomic ratio of from 1.1:1 to 50:1 and at least one of the elements iron, copper, titanium, cobalt, manganese, and nickel and in a given case a carrier material and are prepared by heating to a temperature of 600.degree. to 1100.degree. C. in the presence of oxygen (German Pat. No. 2039497) and related Lussling U.S. Pat. No. 3,923,819, the entire disclosure of which is hereby incorporated by reference and relied upon.
It is true that in this manner high space-time-yields are produced, however, the selectivity of the catalyst is unsatisfactory.